What am I supposed to look at in post game graph?
So yeah? I usually look at damage dealt to champions, taken, turrets, cs, k/d/a. Anything else?
So yeah? I usually look at damage dealt to champions, taken, turrets, cs, k/d/a. Anything else?
Wards
You often find that the people that fail to ward (and/or kill wards) are the ones that get caught out and die more.
Edit: I just realized you said the "post game graph". Sophia covered it though, look at it on the web.
click advanced details and a web browser will open, scroll down to how many wards you placed. under 10: needs improvement 15-20: doing well 20+ great job!
This applies for all lanes. 
Go on the web unless you just wanna do like me and laugh your ass off when you see your outdamaged your mid as the support.
Whatever you want really... The post-game graph is there for your use and enjoyment. But there is nothing there you are "supposed" to look at. If you had a good game and loved how well you did, go ahead and look at whatever you want, knock yourself out.
Are you worried about the graphs? You can choose not to look at it at all and be perfectly fine; the numbers won't really help anything. You already know how you did as well. Now stay with me. The numbers are not inherently meaningful. One game's CS being lower than another doesn't mean you did worse. They're not inherently meaningful because each game is different; that game's CS could be lower because the game was really aggressive and there were fights constantly, for example.
So don't worry that you aren't looking up the right things because you don't need to.
max champion kills